<template>
  <div class="todo-footer">
    <label>
      <input type="checkbox" v-model="isAll"/>
    </label>
    <span> <span>已完成{{doneCount}}</span> / 全部{{todos.length}} </span>
    <button class="btn btn-danger" @click="clearAllDone">清除已完成任务</button>
  </div>
</template>

<script>
export default {
  name: "Footer",
	props:['todos','checkAll','clearAllDone'],
	computed: {
		//已完成数量
		doneCount(){
			return this.todos.filter( todo => todo.done).length
		},
		//是否选中了所有
		isAll:{
			//如果有人修改了isAll属性set函数调用
			set(val){
				//联系父组件去更新所有todo的done值
				this.checkAll(val)
			},
			//如果有人读取了isAll属性get函数调用
			get(){
				return this.todos.length === this.doneCount && this.todos.length > 0
			}
		}
	},
};
</script>

<style scoped>
/*footer*/
.todo-footer {
  height: 40px;
  line-height: 40px;
  padding-left: 6px;
  margin-top: 5px;
}

.todo-footer label {
  display: inline-block;
  margin-right: 20px;
  cursor: pointer;
}

.todo-footer label input {
  position: relative;
  top: -1px;
  vertical-align: middle;
  margin-right: 5px;
}

.todo-footer button {
  float: right;
  margin-top: 5px;
}
</style>